Effects of toremifene and anastrozole on serum lipids and bone metabolism in postmenopausal females with estrogen receptor– positive breast cancer: the results of a 2-year multicenter open randomized study

The potential long-term adverse effects on quality of life have to be considered when selecting agents for adjuvant hormonal treatment for postmenopausal patients with estrogen receptor–positive breast cancer. We performed a 2-year multicenter randomized study to assess the differences in the time course effects between toremifene (TOR) and anastrozole (ANA) on serum lipid profiles and bone metabolism. This study assessed the serum levels of triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), apolipoprotein A-1 (Apo A1), and apolipoprotein B (Apo B) as lipid profiles and bone-specific alkaline phosphatase (BAP) and the N-telopeptide of type-I collagen (NTX) as bone turnover markers in patients who received daily doses of 40 mg and 1 mg for TOR and ANA, respectively. A decreased serum level of TC, LDLC, and Apo B was, respectively, observed at 6 months in 6.2, 12.9, and 13.8% of the patients who received TOR compared with the baseline. These decreases were maintained for at least 24 months. These lipid levels were not changed in those who received ANA. In the TOR patients, there was an increase in the serum level of HDL-C and Apo A1 at 6 months in 17.1 and 16.3%, respectively, which was maintained for at least 24 months, whereas these levels were almost stable in the patients who received ANA. Serum BAP decreased by 12.1% at 12 months and further decreased at 24 months and the serum NTX decreased by 22.0% at 6 months, which was maintained for at least 24 months in the patients who received TOR. In contrast, the serum BAP was increased by 26.0% at 6 months and by 29.2% at 12 months and the serum NTX increased by 21.3% at 24 months compared with baseline in those received ANA. However, the serum BAP increase was not significant at 24 months. TOR provides better effects than ANA in terms of lipid profiles and bone metabolism in postmenopausal females with early breast cancer.